Issue 6 the Silurian January 2020 1
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Issue 6 The Silurian January 2020 1 Issue 6 The Silurian January 2020 Contents Welcome to the sixth edition of the Silurian which contains an eclectic mix of articles, ranging from ideas into the origins of life to art installations inspired by geology. The Origins of Life If you are feeling energetic follow Chris’s 3 Tony Thorp. walk over the cliffs from Aberystwyth to Borth, or for the more sedentary inclined Colin’s geological road journey will add Popular Walks with interest to the trip along the A44 into, or out 7 Interesting Geology. of Wales. Chris Simpson. Finally we all wish Bill Fitches all the best in ‘Cores’ & ‘Crystal forms his new life in Leeds. from the 7 Crystal 11 systems’ Michele Becker Sue Purcell. Six Geological Lineaments of Mid 12 Wales. Submissions Colin Humphrey. Please read this before sending in an article. Please send articles for the magazine digitally as either plain text (.txt) or generic Word format (.doc), and keep formatting to a minimum. Do not include photographs or illustrations The Magazine of the Mid Wales in the document. These should be sent as separate files saved as Geology Club maximum quality JPEG files and sized www.midwalesgeology.org.uk to a minimum size of 1200 pixels on the long side. List captions for the Cover Photo: Electron micrograph of a mitochondria-rich cell. ©Michele Becker photographs at the end of the text, or in a separate file. All photographs and other illustrations are by the author unless otherwise stated. 'Members Photographs' and cover photos are also wanted. Cover photos All rights reserved. No reproduction without need to be in 'portrait' format and a permission. minimum of 3000X2000 pixels. 2 Issue 6 The Silurian January 2020 was described in a letter to the London Electrical Soc. dated 27th December 1837 The Origin(s) of Life (Read 20th Jan, 1838). Andrew Crosse had some credibility as he was one of the first to develop large voltaic piles Introduction and was visited by Sir Humphry Davy (who visited Fyne Court in 1827) amongst others. The two most fundamental questions which The news was subsequently picked up by humans have grappled with since prehistory newspapers across the country and elsewhere are to do with the origin of stuff and the origin in Europe. Some readers apparently gained of life. That we are no different in this age of the impression that Crosse had somehow the internet is evidenced by the literally "created" the insects, or at least claimed to hundreds of books, talks and videos brought have done so. He received angry letters in up by a simple search. Discounting any of a which he was accused of blasphemy and theological nature, every variety of scientist trying to take God's place as a creator. has had his say, all influenced by their particular discipline. Some are prolific popular Although sometimes credited with being the scientific authors with dozens of publications inspiration for Mary Shelley's "Frankenstein", e.g. Paul Davies (physicist), Nick Lane, this was not so because her publication (biologist) and Adam Rutherford (geneticist), antedated Crosse's experiment by 18 years. while others, equally or more credible, have an output more limited to the academic, like John It was only in the 1860s (i.e. contemporary Sutherland (chemist). with the publication of "Origin") that spontaneous generation was finally put to bed Pre-Darwin when Louis Pasteur carried out his famous experiments to prove that sterile broth In the early nineteenth century spontaneous remained sterile if not exposed to particles in generation was a widely held belief, being the air. based on the common observation that stuff goes mouldy and being confirmed by many Another widely held belief was that of reported observations, often amusing to the "Vitalism", which held that life and organic stuff modern intellect. It was even compounded with contained a "vital force" which inorganic the new science of electricity by Andrew materials did not. This held sway until Crosse in a much publicised disproved in 1828 by Friedrich Wohler, who "electrocrystallisation" experiment in which he showed that heating silver cyanate with passed an electric current through a volcanic ammonium chloride produced urea, without rock and small insects were produced. They the aid of a living organism or of a kidney, were named Acarus crossii in his honour. This either of man or dog. Darwin A l t h o u g h D a r w i n w a s contemporary with Mendel, the fact that Mendel's work was not recognised until the turn of the century, meant that Darwin's views on evolution were analogue, although Mendel had shown that heredity was digital. In other words, Darwin would regard the product of crossing white and purple peas as likely to produce various shades of pink, Mendel showed that the progeny were purple or white according to specific rules, determined by “heritable factors”. Fig. 1 From original paper. 14 - 26 show crossii emerging. Although he did not name them, he had discovered genes. 3 Issue 6 The Silurian January 2020 The publication of Darwin's "On the Origin of Cells Species" in 1859 made clear how all species could have originated from one single There was little prospect of determining the ancestor, but shed no light on the origin of that origin of life until there was some simple individual. Darwin himself, considering understanding of what life was and this the existing culture of the time, was depended on the quality of available understandably reticent, but famously made microscopes. Although Robert Hooke, with his comments about the "warm little pond" out of compound microscope, had been the first to which something evolved. More relevantly, in a coin the word "cell" to describe the structure of letter to Hooker, he wrote that ".... it is mere sections of the bark of the cork tree in the rubbish thinking, at present, of origin of life; 1660s, it was Antonie van Leeuwenhoek, with one might as well think of the origin of matter." his single lens microscope who was the first to observe and describe various living infusoria, Well, he was wrong there as physicists have bacteria and other single celled organisms. He pretty well solved the origin of matter, but the was a remarkable amateur scientist who origin of life is proving to be a much harder nut developed a unique microscope with a tiny to crack! Indeed, it was not possible to spherical lens of his own devising, produced progress beyond the "warm little pond" by a technique which was only fully concept until we understood more about what reproduced in 1957. He was somewhat life was! Warm Little Ponds Darwin's speculations about warm ponds presaged the concept of a "Primordial soup" which dominated the search for origins for 100 years. The idea was that, if you took all the ingredients from an early inorganic earth and brewed them up with heat or electricity for long enough, something would emerge. This culminated in the famous experiments conducted by Stanley Miller in 1953, under the supervision of Harold Urey. Miller took the conceived components of a primitive atmosphere i.e. water, methane, hydrogen and ammonia and sparked them with a high voltage. Within a few days, the contents became a rich brown Fig. 2 Stanley Miller's apparatus. Wiki Commons. and analysis revealed the amino acid glycine, together with other biological amino acids, the building secretive about how he made his lenses, blocks of proteins. More recently, the original allowing people to assume that they were samples have been shown to contain all 20 made by grinding. In fact, it is now established biological amino acids plus another five. that his technique was to draw a thin thread of glass and to fuse the end to allow a clear Research has now shown that organic spherical blob to form. He was thus able to chemicals are everywhere, both on the planet produce them as he needed them and and off. Our further understanding of origins produced some 200 in toto! depended on our probing the workings of the cell, and life. Our knowledge of the nature of life progressed rapidly in the mid century. It became clear that 4 Issue 6 The Silurian January 2020 life is cells. Better consisted of proteins and microscopes were becoming DNA. At that time DNA was available and in 1832 regarded as “boring” and Dumortier observed cells of proteins were thought to be algae lengthen and divide the more interesting and in 1833 Robert Brown molecules. Some thought the (well known for his discovery hereditable factor was o f B r o w n i a n M o t i o n ) something to do with shapes examined orchid cells and or grooves in proteins, like a saw and named the cell gramophone record. nucleus. However it was Schwann and Schleiden in Schrodinger recognised that 1837 who put it together as the whole four dimensional "cell theory", but regarded the pattern of an organism's nucleus as the seed from development is determined which the cell developed. It by the structure of one cell, was only in 1854 that Remak the fertilised egg. Moreover, and Virchow realised that all not just by that, but by a cells derive from cells, by small part of it, namely, the division. nucleus of that cell, and indeed, the chromosomes The problem of the origin of within that nucleus. life therefore becomes the problem of the origin of the It is these chromosomes, or first cell, or of something Fig. 3 van Leeuwenhoek's probably only an axial simpler.